Air treating unit



March 12, 1968 1. w. NoRRls ET AL AIR TREATING UNIT 4 Sheets-Sheet lOriginal Filed Dec. 28, 1964 JWM MarCh 12, 1958 J. W. NORRxs ET AI-3,372,879

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4 Sheets-Sheet 5 J. W. NORRIS ET AL.

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4 Sheets-Sheet 4 United States Patent Olhce 3,372,870 Patented Mar. 12,1968 3,372,870 AIR TREATING UNIT .lohn W. Norris, Marshalltown, andWayne F. Sieverding,

Union Grove Lake, Iowa, assignors to Lennox Industries lne., acorporation of Iowa Original application Dec. 28, 1964, Ser. No.421,427, now Patent No. 3,324,782, dated June 13, 1967. Divided and thisapplication Feb. 20, 1967, Ser. No. 632,480

3 Claims. (Cl. 236-13) ABSTRACT F THE DISCLOSURE A mixing damperassembly including a housing having side-by-side inlets for warm air andfor cool air and baille means within the housing for directing warm airin a separate path above the cool air. Dainpers are provided in theplurality of sideeby-side outlets for regulating the temperature of theair discharged through the outlets.

This is a division of application Ser. No. 421,427 led Dec. 28, 1964,now Patent No. 3,324,782.

This invention relates generally to air treating apparatus for heating,cooling and Ventilating and, more particularly, to a novel central airtreating unit capable of producing accurate and instantaneoustemperature control in many zones.

The conditioning of the atmosphere within schoolrooms and similarenclosures which present complex and highly variable requirements forheating, cooling and ventilating represents a difficult problem forwhich presently known air treating units fail to provide an adequatesolution. The particular diiculties encountered in schoolroom heating,cooling and Ventilating will be discussed in detail so as to providefull background for understanding the typical requirements which areeciently fullled by the present invention. It will be understood,however, that the present invention is not limited in any way solely toschoolroom or school construction, but is fully adapted for use in otherbuildings where it is desired to produce accurate and instantaneoustemperature control in many different zones from one central system as,for example, medical centers, motels and hotels, restaurants withprivate dining rooms.

Architects, contractors and air treatment engineers recognize thatclassrooms frequently require cooling even when the outdoor weather isextremely cold. The cooling of such rooms frequently presents a far morechallenging problem than does their heating. Body heat from the personspresent in the classroom, heat from the lighting tixtures and radiantheat from the sun as it strikes the walls, windows and roof, frequentlyproduce heat gains within the room which exceed the normal transmissionor heat losses from the room to the cold outdoor weather. The number ofoccupants in each classroom, their physical size, their bodilyactivities and their lighting requirements vary greatly from room toroom within a schoolhouse and within each room during the course of theday. For example, small children in the lower-class grades transmitrelatively lower total quantities of heat to the room atmosphere than dothe older and larger children of the upperclass grades. There are alsovariations from class to class in the amount of lighting requireddependent upon the reading activities of the various grade levels.

Such factors as recess and lengths of class periods also result in avariety of different and changing conditions of heat load within variousclassrooms. Substantial heat is often needed in order to effect initialwarming of a Classroom during the early morning hours prior to thearrival of the students at the beginning of the school day. After thearrival of the students, the body heat load within the yroom is oftensupplemented by direct sunlight striking against the building as thedaylight hours progress. ln. some instances, one or several of the largenumber of classrooms may be subjected to use during the evening hoursfor adult community activities and the like requiring the maintenance ofproper temperature conditions within only one or a few of a large numberof classrooms within a given schoolhouse. It is apparent therefore, thatconditions within any given classroom may change in a matter of minutesfrom no heat being required to heat being required, or to cooling beingrequired and such varying conditions within one room may be entirelydifferent from the varying conditions and requirements of an immediatelyadjacent room. The maintenance of comfortable temperatures within everyroom is a matter of great importance and it is necessary to effect thecontrol distribution of conditioned air regardless of the outdoorweather conditions` Outdoor air provides an economical source ofrelatively cool air for effecting room cooling during all weatherconditions in which the outside air temperature is lower than acomfortable air temperature desired in side the room. The properheating, cooling and ventilating system for a schoolhouse classroom isone which makes maximum use of outside air for freshening and forcooling and which can very quickly bring in enough outdoor air whenneeded to offset the internal heat gains within the room and keep theroom temperatures from overrunning a thermostat or other controlsetting. Such proper distribution system, therefore, must be one that iscapable of handling either heated air or cool air in a manner that willprovide even and uniform distribution of air` velocity through each roomor area to be treated.

The complex and highly variable requirements for heating, cooling andVentilating of classrooms is met by the air treating system of thepresent invention which is capable of shifting capacity to the areas ofgreatest instantaneous demand so as to reduce the total installedcapacity requirements.

A primary object of` the present invention is to provide an integratedcentral station air treatingunit for a school capable of providing forair heating, cooling and ventilating in accordance with the requirementsof one or more of a plurality of zones withinsuch school.

A further object of the present invention is to provide anintegrated airconditioning or air treating system inco1^- porating a mixing damperconstruction for effectively blending warm air and cool air prior todistribution to one or a plurality of zones to be treated.

Further objects and advantages of this invention will become apparent asthe following description proceeds, and the features of novelty whichcharacterize this invention will be pointed out with particularity inthe claims annexed to and forming part of this specification.

A preferred embodiment to the invention is shown in the accompanyingdrawing, in which:

FIGURE 1 is a perspective view of the central station 5 air treatingassembly of the present invention;

FGURE 2 is a vertical cross-sectional view of the air 3 treatingassembly constructed in accordance with the principles and features ofthe present invention;

FIGURE 3 is a horizontal cross-Sectional view of the air treatingassembly;

FIGURE 4 is an enlarged plan view of the intake and exhaust air unitincorporated in the air treating assembly of the present invention;

FIGURE 5 is an enlarged perspective view of the mixing damper unitincorporated in the air treating assembly of the present invention; and

FIGURE 6 is a perspective view of the baffle employed in the mixingdamper assembly of the present invention.

Referring now to FIGURES l, 2 and 3, there is illustrated the airtreating assembly of the present invention. The air treating assembly 16is comprised of the following major components: a condensing unit 12which may be close coupled, as shown, or which may be located remotefrom the air treating assembly an exhaust and air intake assembly 14; afilter and blower assembly 16; a heating and cooling unit assemblycomprising a heater 18, which may be a direct re heater for any gas orresistance coils for electric heat, and a direct expansion cooling coil19; and a mixing damper assembly 20.

The condensing unit 12 may comprise a condensing coil 22, one or morerefrigerant compressors 23 and the conventional accessory controls forconnecting the condensing coil and compressor in refrigerant circuit. Itis preferred that the condensing -coil be air cooled and appropriatefans 24 are provided for passing air over the coil to condense the hotvaporous refrigerant moving through the tubes within the condensing coil22.

The exhaust and air intake assembly 14 comprises a housing 26 providedin one end wall with exhaust air dampers 2,8 and in another end wallwith outdoor air intake grille 30. An opening 32 is provided in thebottom of the housing 26 for communicating with the room or area to beconditioned. Thus return air enters the air treating unit 10 throughopening 32. Upright walls 34 and 35 are provided in the housing 26 ateither side of the inlet opening 32. The wall member 34 is imperforateso as to separate the incoming outdoor air from the air being returnedto the air treating assembly from the area or areas to be conditioned.The upright wall 35 is provided with louvers or dampers 36 so as topermit regulated passage of the return air from the area or areas beingtreated to the atmosphere through the exhaust air dampers 28. Dampers 37are provided in a side wall of the housing 26 to communicate the inletair with the blower assembly 16. Also provided in the side wall ofhousing 26 are dampers 38. The dampers 38, which are in communicationwith the outdoor air inlet dampers 30, permit the passage of outdoor airto the blower and filter unit 16.

-Dampers 28 are pivoted at the top so as to be normally closed. Theyfunction as light back-draft dampers to prevent entry of outdoor airinto the exhaust and air intake unit 14 when the exhaust fan 40 isinoperative.

The dampers 28 are opened only by the pressure of exhaust fan 40, whichis provided to assure the use of oneh-undred-percent outside air whenneeded. Fan 40 is operatively driven by motor 42. The motor and fan aresupported on bracket 43 within housing 26.

Afixed to bracket 43 adjacent motor 40 is a modulating damper motor 44for simultaneously actuating dampers 36, 37 and 38 to properly regulatethe quantities of outside air, return air, and exhaust air passingthrough housing 26. The dampers 36, 37 and 38 are interconnected withmodulating damper motor 44 by means of linkage 45 (FIGURE 4).

The dampers 36, 37 and 38 are sized so that onehundred percent of theair handled by the unit can go through any one of the three damper sets.This allows one-hundred-percent recirculation, or one-hundred-percentoutside air with assured exhaust to make it possible, or any mixturethereof.

The modulating motor 44 is commanded by a combination of mixed airtemperature downstream from the blowers and outside air temperature.

Regulated quantities of outside air and/or return air are drawn fromhousing 26 through dampers 38 and 37, respectively, by blowers 46. Theblowers 46 are driven by motor 48 operatively connected to the blower bya belt and pulley drive arrangement 49. Preferably, all the moving partsof the blower assembly-namely, the blower wheels, shafting, bearings,drives and motor-are mounted in a rigid frame. The entire subassembly ofmoving parts is resiliently suspended in the housing or cabinet 16.

The blowers d6 draw air through filter 50. Filter 50, which may be madefrom a highly efcient urethane foam filter material, is detachablyconnected in blower and filter unit 16. The filter can be vacuum cleanedin place, if desired, and a 11S-volt convenience outlet is provided inthe unit 16 for convenient connection of a tank-type domestic vacuumcleaner.

The discharge of air from blowers 46 is suitably directed by batiies 52,which are interconnected to one another by linkage 53 and are actuatedby damper motor 54. Air may be directed primarily to the heater 1S or tothe cooler 19 for suitable conditioning.

The heater 1S may be a gas-fired furnace or an electric resistance-typeunit.

The cooling coil or evaporator 19 is operatively connected in arefrigerant circuit with the condenser 22 in the condensing unit 12. `Aswill be apparent to those skilled in the art, the cooling componentsneed not be incorporated into the air treating unit 10 initially, butcan easily be added at a later time by virtue of the design of theassembly 10.

The warm air and the cool air discharged from the heater 13 andevaporator 19, respectively, flows into the mixing damper assembly 2)for suitable blending of the air prior to discharge into the conduitsleading to the rooms to be treated. The inlet openings to the mixingdamper assembly are disposed in side-by-side relationship in one side ofthe housing defining assembly 20.

The warm air from heater 18 is guided below stationary bafiie 64) anduniformly spread across the width of the compartment defined belowbaflie 60 as indicated by the dotted arrow lines in FIGURE 3. The coolair from coil 19 is guided above batiie 60 and uniformly spread acrossthe width of the compartment defined above baie 60 as indicated by thesolid `arrow lines in FIGURE 3.

Provided in the entrance to each of the compartments 64-73 defined atthe rear of unit 2t) by upright divider plates 64a-72a are damper means75 for regulating the quantity of air entering each compartment. As seenin FIGURE 5, each damper means comprises an upper damper 76 forregulating the cool air entering a mixing compartment and a lower damper77 for regulating the warm air entering the mixing compartment. Thedampers 76 and 77 are mounted upon a common shaft 78. Rotation of theshaft will move one damper toward open position and the other dampertoward closed position. Modulating damper imotor 75 is operativelyconnected to the shafts 78 for actuating the dampers in response to apredetermined condition.

The opening in the bottom of each compartment 64- 73 is connected with aconduit for conducting the treated air to a room. If desired, theopenings may be formed in the rear wall of unit 20 rather than in thebottom. There may be as many compartments as zones to be treated. It isnoted that ten compartments are shown in FIGURE 3 and eight compartmentsare shown in FIG- URE 5.

Referring to FIGURE 6, there is `better seen the construction of lbaffle60. The baffle includes a plate 79 having a sharply upwardly inclinedportion 86 having a flange 81 at the front thereof generally inalignment with the heater 18 and a slightly upwardly inclined portion 82having a ange 83 at the front thereof generally in alignment with thecoil 19. The inner edges of Wall portions 30 and 82 are connected by avertical divider wall 84.

The flow directing baffle 6) guides the air discharged from the heater18 and coil 19 into the mixing damper unit 20 in iiow paths that areseparated from another. The segregated air is directed uniformly intothe compartments 64-73 for proper mixing and blending within eachcompartment.

Control of the air temperature in the air treating unit 1t) is obtainedthrough control elements, such as ductstats located downstream from theheater 18 and the cooling coil 19. The ductstats may use long capillarytubes to sense an average lair temperature.

On the heating side, the ductstat is compensated in accordance withoutside air temperature in a predetermined rnanner, as for example, on aone-to-One basis. Assuming a one-to-one basis, as outside airtemperature drops one degree, the ductstat allows one degree warmer airto be maintained on the hot side of the system. The effect of this is tomodulate the hot side temperature that is continuously available to themixing dampers.

On the cooling side, the ductstat is normally set to maintain apredetermined temperature below normal room temperature on the cold sideof the system. For example, the ductstat may be set to maintain about 55F. whenever outdoor temperature is 55 F. or above. As the outdoortemperature drops -below 55o F., the cornpressors 23 are shut offbecause outdoor air temperature now has adequate capacity to do all ofthe cooling required.

Inlet air to the blowers 46 is normally a mixture of outside air andreturn air when the air treating apparatus is in use land theschoolhouse is occupied. A hydraulic bulb which senses mixed airtemperature from the downstream side of the blowers modulates dampermotor 44 to move the dampers 36, 37 and 38 to positions to maintain apredetermined mixed air temperature. A temperature of about 60 F. hasbeen found satisfactory for etiicient operation of the system. Thisprovides proper air freshening and `ventilation and adequate cooling bymeans of the use of outside air (rather than the cooling coil) withoutbeing a burden to heating for those zones or areas requiring heating. Attemperatures above the selected temperature condition, the dampers willbe open to onehundred-percent outside air until attainment of higherpredetermined temperature, about 67c F., at which point the dampers arereturned to the minimum position yfor required ventilation.

At outside temperatures below 60 F., the dampers 36, 37 and 38 willmodulate to a position of outside and return air that provides -a mixedair temperature of 60 F.

Control of the temperature in a room or Zone is obtained by a roomthermostat which commands the threeposition ldamper motor 75 whichactuates the mixing damper or dampers feeding to that zone. It will beunderstood that there may be one damper motor for each upper and lowerdamper or that one damper motor may control a plurality of upper andlower dampers.

The air treating system of the present invention is ideally suited foruse in meeting the variable land cornplex heating and coolingrequirements in multizone buildings, as for example, schoolhouses,medical centers, and motels. The complete heavily-insulated outdoorpackage is assembled, wired, and piped at the factory, thus requiringminimum installation costs on the job site. Though the air treatingsystem may be conveniently mounted on a roof top, it can easily beinstalled on a slab adjacent to the building or even installed in anequipment room, if required by the building design.

Integrated within the air treating assembly are air dampers that controlreturn air, outside air, and exhaust air, all the dampers beinginterconnected and actuated by an electric modulating damper motor. Apowered exhaust fan is provided to assure the use of one-hundredpercentoutside air when needed. The dampers can be adjusted to continuouslyintroduce the amount of outside air required for proper freshening andodor removal during all periods of occupancy. During nonroccupiedperiods, one-hundred-percent recirculated air may be used for economy.

A mixing damper assembly is provided in the air treating unit forsupplying a plurality of separate zones with desired conditioned air.The mixing damper assembly is capable of shifting capacity to areas ofgreatest instantaneous demand, thereby reducing the total installedcapacity. For certain applications, for example, when the system isinstalled for dual duct distribution the mixing damper assembly isomitted and the discharge from the heater i8 and the direct expansioncoil 19 communicates with a warm air duct and a cool air duct,respectively, for transmission to a mixing box adjacent to the area tobe treated. Thus, it is seen that the air treating system of the presentinvention provides for great design flexibility.

While there has been shown and described a particular embodiment of thisinvention, it will be obvious to those skilled in the `art that variouschanges and modifications may be made therein Without departing from theinvention and, therefore, it is intended in the appended claims to coverall such changes and modifications as fall within the true spirit andscope of the invention.

We claim:

1. In a mixing damper assembly for an air treating unit, the combinationof a tubular housing having a Warm air inlet and a cool air inlet inside-by-side relationship in one side thereof, a stationary baffle platedisposed transversely in said housing intermediate the top and bottomwalls thereof for directing the Warm air and the cool air enteringthrough said inlets transversely from the Warm air inlet and cool airinlet, respectively, .in separate iiow paths, means defining a pluralityof compartments in said housing, damper means in the entrances to thecompartments for controlling the yquantity of warm air and cool airintroduced into the compartments, and the control lmeans for regulatingthe damper means in response to predetermined temperature requirements.

2. An air treating unit for continuously recirculating room air andconditioning the iiow thereof with warm air, and cool air comprising amixing damper assembly including a housing having a Warm air inlet and acool air inlet defined in one end wall thereof, said inlets being spacedfrom another in side-by-side relationship, there being a plurality ofoutlet openings in said housing remote from the inlets, upright dividerplate spaced from one another for defining a plurality of mixingcompartments within said housing, damper means supported in the entranceto each compartment for selectively regulating the flow of warm air andcool air into each compartment, said damper means comprising an upperdamper and a lower damper affixed to a common shaft, and a baie plate insaid housing for directing the Warm air from the warm air inlettransversely of the housing to each compartment in a lower flow path andfor directing the cool air from the cool air inlet transversely of thehousing to each compartment in an upper iiow path separate from saidlower flow path, and control means for actuating said damper means inresponse to a predetermined condition to regulate the temperature of theair discharged from each compartment to a point of use.

3. A mixing damper assembly for use in an integrated roof-supported airconditioning unit comprising a housing having a Warm air inlet and acool air inlet detined in one end Wall thereof, said inlets being spacedfrom one another in side-by-side relationship, there being a pluralityof outlet openings in the bottom of the housing adjacent the other endwall, spaced divider plate means in said housing for dening acompartment adjacent each outlet opening, damper means Supported formovement about upright axes extending in spaced relationshiptransversely of the housing for regulating the flow into each compart-3,372,870 7 ment, said damper means `comprising an upper damper eect adesired controlled mixing of the two supplies, and a lower damperaffixed to a ,Common Shaft, Wan and control means for actuating thedamper means.

gndlfg genfugfgnsrsylm.Sei oufgg bell References @ses eens wamalrme insal c o alrme s1 Wa T means directing Warm air transversely of thehousing to 5 UNITED STATES PATENTS each compartment and directing thecool air transversely 1 Q15204 1/1912 Muffyv 236-13 of said housing toeach compartment in a path separate I/[cd 2362361-3-1; from andgenerally above said Warm air, whereby the Oms e a cool air and Warm airsupplies are transferred from side- 10 EDWARD 1 MICHAEL Pfl-maryExaminer. by-side relationship to under and over relationship to

